High-potential switching system.



C. P. STEINMETZ. HIGH POTENTIAL swncume SYSTEM.

APPLICATION FILED JAN-28, 19l3.

Patented Oct. 19, 1915.

[N YENTUH. CHARLES P STEJNME'TZ .BY g 5 $1 2.5 ATTUHNE'Y I I ZTNESSEE 64oz a UNITED STATES PATENT OFFICE.

CHARLES P. STEINMETZ, OF SCHE NECTADY, NEW YORK, ASSIGNOR T0 GENERAL ELECTRIC COMPANY, A CORPORATION OF NEW YORK.

. HIGH-POTENTIAL SWITCHING SYSTEM.

Specification of Letters Patent.

Patented Oct. 19, 1915.

Application filed January 28, 1913. Serial No. 744,803.

To all whom it may concern:

Be it known that I, CHARLES P. STEIN- Mnrz, a citizen of the United States, residing at Schenectady, in the county of Schenectady, State of New York, have invented certain new and useful Improvements in High-Potential Switching Systems, of which the following is aspecification.

My invention has reference to a method and apparatus for connecting a source of high potential energy to and disconnecting it from one or more conductors, and, more particularly, to such a system in which the conductors are high tension transmission lines. High tension switching of transmission lines on very high voltages has heretofore been dangerous, as it tends to produce oscillations which are liable to become cumulative, especially in circuits in which the effective resistance periodically varies, due to magnetic or dielectric hysteresis losses and similar phenomena, and under these conditions the oscillations become destructive. High tension switching is, therefore, generally avoided and the switching done on the low tension side of the transformers. This, however, is not always feasible and high tension switching then becomes necessary, as for instance when several transmission lines issue from the same high tension bus of the generating station, or where a branch line connects to the main line, or where the main line passes through a stepdown station and its continuation beyond this station has to be disconnected in case of trouble.

My invention overcomes the difliculties above indicated that have heretofore been experienced, by providing a method pf energizing the high tension line before it is directly switched in and maintaining it energized until after it is switched out.

For a better understanding of my invention reference may be had to the accompanying drawing, in which I have diagrammatically illustrated one embodiment of my invention, as applied to a three-phase system.

The three phase transmission line A is shown as the line to be connected to the con ductors B which carry high potential energy supplied by a generator D through the transformer E. For directly connecting the conductors A to the conductors B, I provide a main switch S. In shunt to the main switch S is provided a separate path between the conductors A and B which is opened and closed by an auxiliary switch 8. Between the switch 8 and the high potential conductors B a step-down transformer T is placed and between the switch 8 and the conductors A of the line to be connected, is a step-up transformer t and resistance 7. Between the low tension sides of the transformers T and t the switch 8 is operated, the main switch S and the auxiliary switch 3 being preferably interconnected as diagrammatically shown by the link C and so arranged that the auxiliary switch 8 closes its contacts 8 before the main switch S engages its contacts S. Conductors Gr are shown as leading to a consumers station from the low tension side of the transformer T.

The operation of my device is as follows: When the line A is to be connected to the source of energy supplythrough conductors B, the low tension or auxiliary switch .9 is first closed and the lines A thereby energized from the conductors B to substantially the potential of the source of energy, and due to the low tension switching, this occurs without disturbance. Immediately afterward the high tension or main switch Sis closed, and, as the line A is already at substantially the potential of the source of energy, this switch also closes without producing surges or disastrous disturbances upon the system. The line A is disconnected from the conductors B and the source of energy supply, by first opening the mainswitch S and then the auxiliary switch a. When the main switch S opens, no disturbances are produced, as the switch disconnects lines of substantially the same potential, the potential on the line A being maintained through the separate or 'shunt path through the switch 8. When switch 8 opens it merely opens a low tension circuit with no dangerous surge efiects. The transformer 2? thus needs to have only sulficient size to carry the capacity current of the line A for a short time, and in general may be small.

The resistances r in the low tension circuit of the switch 8 are chosen so as to allow sufiicient current topass to fairly energize the lines A but to limit the current which would flow in transformer 23 in case of a short circuit on the line A after the switch S and before the switch 8 is opened.

In accordance with the provisions of theciple of operation of my invention, together with the apparatus which I now consider to represent the best embodiment thereof.

My invention may be embodied in many other forms than that shown and described and I, therefore, do not wish to be restricted to the precise construction shown, but intend to cover by the appended claims all changes and modifications which are within the scope of my invention and will be apparent to those skilled in the art.

lVhat I claim as new and desire to secure by Letters Patent of the United States is 1. The method of directly connecting a source of energy supply to and disconnecting it from one or more conductors, which consists in providing a separate path for the energy having a permanent lower potential than the source ofsupply, making the connections in the separate path, then connecting the source of supply directly to the conductors, then directly disconnecting the source of supply from the conductors and then breaking the connections in the separate path.

2. The method of connecting a source of energy supply to a transmission line, which consists in first raising the potential of the line to substantially the potential of the source of energy through a separate path in inductive relation to said source of energy and to said line and always at a lower potential than either said source of energy or said line, and then connecting said line directly to said source of energy.

3. The method of disconnecting a source of energy supply from a transmission line, which consists in first opening a direct connection' between said line and said source of energy, then maintaining the potential of said line at substantially the potential of said source of energy through a separate path in inductive relation to both said source of energy and said line which path is always of lower potential than either said source of energy or said line, and then opening the circuit through said Separate path.

4. The combination with a source of energy and a transmission line, of means for connecting said line to said source of energy comprising, a switch for directly connecting said source of energy to said line, a normally open shunt path to said switch maintained at a lower potential than either said source of energy or said line, means in said path for raising said line to substantially the potential of said source of energy when said path is closed, and a switch for closing said path prior to the closing of said first switch.

5. The combination'of a source of energy and a transmission line, of means for connecting said line to said source of energy comprising, a separate path between said source of energy and said line, contacts in said path maintained at a lower potential than either said source of energy or said line. means for bridging said contacts, and means in inductive relation to said line and to said source of energy for raising the po-' tential of said line to substantially the potential oi said source when said contacts are bridged. and means for subsequently short circuiting said path.

(3. in combination, a source of energy supply. a trai'ismission line, a switch for directly connecting said source of energy to said line, a path of permanently lower potential than either said source of energy or said line in shunt to said switch, transformers in said path for raising the potential of said line to substantially the potential of said source of energy, and a switch for closing said shunt path prior to the direct connection of said source of energy to said line.

7. In combination, a source of energy supply, a transmission line, a set of contacts adapted when bridged to directly connect said source of energy to said transmission line, a second set of contacts in a separate path between said source of energy and said line, means in said path for maintaining said second set of contactsalways at a lower potential than either said source of energy or said line, and means for connecting said line to said source of energy first by bridging said second set of contacts and then bridging said first set of contacts and for disconnecting said line from said source of energy in the reverse order.

8. In combination, thesource of energy, a transn'iission line, a switch for directly connecting and disconnecting said source of energy from said line, a shunt path to said switch always at a lower potential than either said source of energy or said line, means in said path for maintaining said line at substantially the potential of the source of energy before said switch closes and after said s itch opens, and means for first connecting said line to said source of energy and finally disconnecting said line from said source of energy through said shunt path.

9. In combination, a source of energy, a transmission line connected thereto, a switch for directly disconnecting said line from said source of energy, a shunt path to said switch always at a lower potential than either said source of energy or said line, means in said path for maintaining said line at substantially the potential of said source of energy after said switch opens, and a second switch for finally disconnecting said source of energy from said line through said low potential shunt path.

10. In combination, a source of energy, a transmission line, means for connecting said line to said source of energy through a separate path of low potential, means responsive -to the closing of said separate path for raising the potential of said line to substantially the potential of said source of energy, and means for finally directly connecting said source of energy to said line.

11. In combination, a source of high potential energy supply, a high tension transmission line directly connected thereto, means including a transformer for conveying the energy from said source of supply to said transmission line at a potential lower than either the source of supply or that carried by the transmission line, and means comprising switches located directly between the source of energy supply and said trans mission line, and in said first named means, respectively, for first connecting said source of energy supply to said transmission line where the energy is at a lower potential than the source of energy supply, and then connecting the source of supply directly to said transmission line.

In witness whereof, I have hereunto set my hand this 27th day of January 1913.

CHARLES P. STEINMETZ.

Witnesses:

BENJAMIN B. HULL, HELEN ORFORD. 

